Pump apparatus

ABSTRACT

A pump apparatus which can save space and is easy to handle is proposed. The pump apparatus includes a pipe-shaped casing including a suction port and a discharge port arranged in the same straight line and defining a flow channel that connects the suction port and the discharge port; a motor disposed inside the casing, the motor including a rotating shaft extending along a flow channel direction directing from the suction port to the discharge port, a rotor rotating integrally with the rotating shaft, a stator provided on an outer peripheral side of the rotor, and a can for isolating a rotor chamber and a stator chamber, the rotor chamber having the rotor disposed therein and the stator chamber having the stator disposed therein; and an inverter disposed in the interior of the casing for exercising variable speed control over the motor.

TECHNICAL FIELD

The present invention relates to a pump apparatus.

BACKGROUND ART

In the related art, an inline pump including a suction port and adischarge port arranged in the same straight line is known (for example,see PTL 1). The inline pump described in PTL 1 includes a pump casingincluding an outer cylinder configured to connect the suction port andthe discharge port, and a motor provided in the pump casing. The inlinepump achieves a high lift without increasing the outer diameter of thepump by using a variable frequency inverter and driving the motor at ahigher speed than a commercial frequency of 50 to 60 Hz.

CITATION LIST Patent Literature

PTL 1: Japanese Patent Laid-Open No. 5-332282

SUMMARY OF INVENTION Technical Problem

In general, the pump apparatus is disposed adjacent to a building ordisposed in a pump room in the building, when used, for example, forsupplying water to the building. However, to dispose the pump apparatusadjacent to the building, a space is needed outdoors. In addition, todispose the pump apparatus in the building, a pump room for disposingthe pump apparatus is needed, which may occupy an available space in thebuilding. In particular, in the case of a high-building with manylevels, if the pump apparatus is disposed on a middle level for pumpingwater to higher levels, a useful space on the middle level is occupiedfor disposing the pump apparatus.

The present invention is made in view of such circumstances, and it isone of objects of the present invention to propose a pump apparatus thatcan save space and is easy to handle.

Solution to Problem

An embodiment of the present invention proposes a pump apparatus. Thepump apparatus includes: a pipe-shaped casing including a suction portand a discharge port arranged in the same straight line and defining aflow channel that connects the suction port and the discharge port; amotor disposed inside the casing, the motor including: a rotating shaftextending along a flow channel direction directing from the suction portto the discharge port; a rotor rotating integrally with the rotatingshaft; a stator provided on an outer peripheral side of the rotor; and acan for isolating a rotor chamber and a stator chamber, the rotorchamber having the rotor disposed therein and the stator chamber havingthe stator disposed therein; and an inverter disposed in the interior ofthe casing for exercising variable speed control over the motor.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a drawing illustrating a schematic configuration of a pumpapparatus according to an embodiment of the present invention.

FIG. 2 is a pattern diagram illustrating schematic functions of the pumpapparatus according to the embodiment.

FIG. 3 is a drawing illustrating a schematic configuration of a pressuretank according to the embodiment.

FIG. 4 is a drawing illustrating an example of a water supply systemusing the pump apparatus of the embodiment.

FIG. 5 is a drawing illustrating a power line communication in theembodiment.

FIG. 6 is a drawing illustrating a schematic configuration of a watersupply system according to a modification.

FIG. 7 is a drawing illustrating a schematic configuration of a watersupply system according to another modification.

FIG. 8 is a drawing illustrating a schematic configuration of a watersupply system according to still another modification.

FIG. 9 is a drawing illustrating another application of the pumpapparatus.

FIG. 10 is a drawing illustrating a schematic configuration of a pumpapparatus according to a modification.

DESCRIPTION OF EMBODIMENT

Referring now to the drawings, an embodiment of the present inventionwill be described. The drawings used here, however, are patterndiagrams. Therefore, the size, location, and shape of illustrated partsmay differ from the size, location, and shape of those in an actualapparatus. In the following description and the drawings used in thefollowing description, the parts having the same configuration aredenoted by the same reference signs, and redundant explanations areomitted.

(Pump Apparatus)

FIG. 1 is a drawing illustrating a schematic configuration of a pumpapparatus according to an embodiment of the present invention. Forexample, a pump apparatus 10 of the embodiment may be used as a watersupply apparatus for supplying tap water to a water supply target suchas a building or a fire-extinguishing apparatus in thefire-extinguishing system. The pump apparatus 10 of the embodimentincludes a plurality of casing members (first to fourth casing members21 to 24) in each of which components of the pump apparatus 10 areseparately housed and supported. The plurality of casing members and thecomponents are connected to each other. In FIG. 1, the first to fourthcasing members 21 to 24 and the components housed in the interiorthereof are illustrated as an exploded diagram. However, theconfiguration is not limited to the described example, and the pumpapparatus may be configured to be supported generally by a single casingmember.

The pump apparatus 10 illustrated in FIG. 1 includes a casing 20configured to define an outline of the apparatus. The casing 20generally has a cylindrical pipe shape as a whole. One end (a lower endin FIG. 1) of the casing 20 defines a suction port 26 of the pumpapparatus 10, and the other end (an upper end in FIG. 1) of the casing20 defines a discharge port 27 of the pump apparatus 10. Note that thepump apparatus 10 may further include components connected respectivelyto the upstream (lower side in FIG. 1) and the downstream (upper side inFIG. 1) of the configuration illustrated in FIG. 1. When the additionalcomponent is connected to the upstream side, the upstream end of thecomponent may be configured as the suction port 26. When the additionalcomponent is connected to the downstream side, the downstream end of thecomponent may be configured as the discharge port 27. The casing 20defines a flow channel that connects the suction port 26 and thedischarge port 27 in the interior thereof. Although not limiting, boldarrows in FIG. 1 indicates a flow of a carrier liquid. In FIG. 1, thecarrier liquid flows upward from the bottom of the pump apparatus 10.The direction of the flow of the carrier liquid connecting the suctionport 26 and the discharge port 27 (vertical direction in FIG. 1) isreferred to as a “flow channel direction Af”. Note that although thepump apparatus 10 illustrated in FIG. 1 is indicated such that the flowchannel direction Af extends along an up-down direction, the pumpapparatus 10 may be disposed at any angle. For example, the pumpapparatus 10 may be disposed so that the flow channel direction Afextends along the vertical direction or the flow channel direction Afextends along the horizontal direction.

In the embodiment, the casing 20 includes four casing members (first tofourth casing members 21 to 24). The first to fourth casing members 21to 24 are arranged in line in the flow channel direction, and defineflow channels, respectively, for the carrier liquid. In the exampleillustrated in FIG. 1, from the upstream (primary side) to thedownstream (secondary side) in the flow channel direction Af, the fourthcasing member 24, the first casing member 21, the second casing member22, and the third casing member 23 are arranged in this order. The firstto fourth casing members 21 to 24 may be connected to each other withfasteners such as bolts.

A motor 30 is housed in the interior of the first casing member 21. Thefirst casing member 21 includes a piping frame 211 that defines anoutside surface of the pump apparatus 10 and a motor frame 212 locatedin the interior of the piping frame 211 and having the motor 30 housedtherein. In the example illustrated in FIG. 1, the piping frame 211 andthe motor frame 212 have a cylindrical shape, respectively, and arearranged concentrically about the rotating shaft of the motor 30. Thepiping frame 211 and the motor frame 212 are fixed to each other or areconfigured as a unitary member, and the flow channel is defined betweenthe piping frame 211 and the motor frame 212. In other words, in theembodiment the flow channel for the carrier liquid is defined on theouter periphery of the motor 30.

The motor 30 includes a rotating shaft 31 extending along the flowchannel direction Af, a rotor 32 rotating integrally with the rotatingshaft 31, and a stator 33 provided on the outer peripheral side of therotor 32. In the embodiment an IPM motor in which a permanent magnet 32a is embedded in the interior of the rotor 32 is employed as the motor30. However, an SPM motor having the permanent magnet 32 a on thesurface of the rotor 32 may also be employed as the motor 30. The motor30 is not limited to those having the rotor 32 provided with thepermanent magnet 32 a and may be an induction motor or an SR (SwitchedReluctance motor), and the like. The stator 33 is fixed to an innerperipheral side of the motor frame 212. A thin cylindrical shaped can 36is disposed on an inner peripheral side of the stator 33. The materialthat can be used for the can 36 may be a metal material such asstainless steel, or a resin material such as PPS. The motor frame 212and the can 36 are disposed concentrically about the rotating shaft 31.Disposed between the can 36 and the motor frame 212 is a frame sideplate 214. Note that the frame side plate 214 is disposed only on oneend side (the lower side in FIG. 1) of the stator 33 in the exampleillustrated in FIG. 1, but the frame side plate 214 may also be disposedon the other end side (the upper side in FIG. 1) of the stator 33. Themotor frame 212, the can 36, and the frame side plate 214 define astator chamber in which the stator 33 is disposed.

A first impeller 41 and a bearing 42 for axially supporting the firstimpeller 41 are housed in the interior of the second casing member 22.The first impeller 41 includes a first impeller rotating shaft 41 aconfigured to be connectable to the rotating shaft 31 of the motor 30.The first impeller rotating shaft 41 a and the rotating shaft 31 of themotor 30 may respectively have a convex and a concave, for example, tobe fitted to each other, so as to rotate integrally when connected toeach other. The first impeller rotating shaft 41 a and the rotatingshaft 31 of the motor 30 may be connected to each other via a shaftcoupling. The second casing member 22 supports the bearing 42 andsupports the first impeller 41 via the bearing 42. The second casingmember 22 may be formed to have an interior having a shape in conformitywith the shape of the first impeller 41 so that the carrier liquid ispumped from the suction port 26 toward the discharge port 27 by therotation of the first impeller 41. For example, the second casing member22 may have a diffuser, a guide vane, or the like.

A second impeller 43 and a bearing 44 for axially supporting the secondimpeller 43 are housed in the interior of the third casing member 23.The second impeller 43 includes a second impeller rotating shaft 43 aconfigured to be connectable to the first impeller rotating shaft 41 a.The second impeller rotating shaft 43 a and the first impeller rotatingshaft 41 a may respectively have a convex and a concave, for example, tobe fitted to each other, so as to rotate integrally when connected toeach other. The second impeller rotating shaft 43 a and the firstimpeller rotating shaft 41 a may be connected to each other via a shaftcoupling. The third casing member 23 supports the bearing 44 andsupports the second impeller 43 via the bearing 44. The third casingmember 23 may be formed to have an interior having a shape in conformitywith the shape of the second impeller 43 so that the carrier liquid ispumped from the suction port 26 toward the discharge port 27 by therotation of the second impeller 43. For example, the third casing member23 may have a diffuser, a guide vane, or the like.

As described above, in the example illustrated in FIG. 1, the secondcasing member 22 in which the first impeller 41 is housed and the thirdcasing member 23 in which the second impeller 43 is housed are connectedto the first casing member 21 in which the motor 30 is housed, so thatthe pump apparatus 10 having the two-stage impeller is achieved. Thepump apparatus 10 here may be configured as the pump apparatus 10 notincluding the third casing member 23 and the second impeller 43 butincluding a single-stage impeller. The pump apparatus 10 may also beconfigured as a pump apparatus having a plurality of, three or morestages by connecting a casing member in which still another impeller ishoused. In the pump apparatus 10 of the embodiment, a single impeller ishoused in a single casing member, and a pump apparatus having a desirednumber of impellers may be configured by connecting a plurality ofcasing members corresponding to the desired lifting height of the pumpapparatus 10. Note that although it is described that a single impelleris housed in a single casing in the embodiment, two or more impellersmay be housed in the single casing member.

The fourth casing member 24 includes an inverter 51, a controller 53, apower line communication unit (PLC unit) 52, and a sensor 54 housed inthe interior thereof. The fourth casing member 24 supports thesecomponents. However, at least one of the inverter 51, the controller 53,the PLC unit 52, and the sensor 54 may be housed in another casingmember or may be divided and housed in a plurality of casing members.Note that in the example illustrated in FIG. 1, the fourth casing member24 includes a first frame 241 that defines an outside surface of thepump apparatus 10, and a second frame 242 located in the interior of thefirst frame 241 and configured to house the inverter 51 or the like. Inthe example illustrated in FIG. 1, the first frame 241 and the secondframe 242 have a cylindrical shape, respectively, and are arrangedconcentrically about the rotating shaft of the motor 30. The pipingframe 211 and the motor frame 212 are fixed to each other or areconfigured as a unitary member, and the flow channel is defined betweenthe first frame 241 and the second frame 242. In other words, in theembodiment the flow channel for the carrier liquid is defined on theouter periphery of the inverter 51 or the like. However, theconfiguration is not limited to the example described above, and such aconfiguration is also applicable that the inverter 51 or the like isformed into an annular shape and is disposed on the outer peripheralside in the interior of the fourth casing member 24 to allow the carrierliquid to flow inside the inverter 51 or the like.

The inverter 51 is provided for exercising variable speed control overthe motor 30. The inverter 51 and the motor 30 are electricallyconnected to each other by a connection between a connector 51 aconnected to the inverter 51 and a connector 30 a connected to the motor30 (stator 33). The connectors 30 a and Ma may employ various knownmechanisms. Accordingly, assembling and disassembling of the firstcasing member 21 and the motor 30 to and from the fourth casing member24 and the inverter 51 can be achieved easily. The controller 53 isprovided to control the entire pump apparatus 10. The PLC unit 52 cancommunicate with the controller 53 and is configured to be capable ofperforming communication using a power line 110 for supplying power tothe pump apparatus 10 as a communication line. Examples of thecommunication destinations by the PLC unit 52 include a control panelprovided outside the pump apparatus 10, a monitoring device, or a PLCunit provided in another pump apparatus.

The sensor 54 is provided for detecting various types of operationinformation of the pump apparatus 10. In the embodiment, the sensor 54includes pressure sensors 63 and 64 and a flow switch 66 describedlater. However, the configuration is not limited to the describedexample, and only a sensor for monitoring the status of the pumpapparatus 10 needs to be included as the sensor 54. For example, thesensor 54 may include a temperature sensor for detecting the temperatureof at least one of the components of the pump apparatus 10, such as thetemperature of the motor 30, the temperature of the inverter 51, and thetemperature of the controller 53. The sensor 54 may also include avibration sensor for detecting the vibration of at least one of thecomponents of the pump apparatus 10, such as the vibration of the casing20, the vibration of the bearings 42 and 44, and the vibration of therotating shaft 31. The sensor 54 may further include a flow rate sensorfor detecting the flow rate of the carrier liquid. The sensor 54 mayalso include a current sensor for detecting the current flowing in thepump apparatus 10 or the motor 30. Furthermore, the sensor 54 mayinclude a sensor for monitoring the magnitude of the noise generated bythe pump apparatus 10.

FIG. 2 is a pattern diagram illustrating schematic functions of the pumpapparatus 10 according to the embodiment. Note that in FIG. 2, theconfigurations corresponding to those illustrated in FIG. 1 are denotedby the same reference signs and redundant description is omitted. InFIG. 2, the configuration not illustrated in FIG. 1 is partly added inillustration. As illustrated in FIG. 2, the pump apparatus 10 isconfigured to be capable of pumping the carrier liquid from the suctionport 26 to the discharge port 27 by a pump 40 having impellers (thefirst impeller 41 and the second impeller 43 in the example illustratedin FIG. 1). Here, the suction port 26 may be connected to a supplysource of the carrier liquid, not illustrated, such as a water main or awater receiving tank, and the discharge port 27 may be connected to anobject to be supplied with the carrier liquid, not illustrated, such asa water outlet of the building.

Check valves 62 a and 62 b are provided on the upstream side and thedownstream side of the pump 40. The check valves 62 a and 62 b preventthe backflow of water when the pump 40 is stopped. A pressure sensor 63is provided upstream of the check valve 62 a. The pressure sensor 63 isa pressure measuring device for measuring the suction pressure of thepump 40. Note that the check valve 62 a and the pressure sensor 63provided upstream of the pump 40 may be omitted in the case where awater receiving tank is connected to the suction port 26 of the pumpapparatus 10. A flow switch 66 is provided downstream of the check valve62 b. The flow switch 66 is a flow rate detector configured to detectthe fact that the flow rate of the carrier liquid to be discharged fromthe pump 40 is lowered to a predetermined value, that is, theunderquantity of water (small quantity of water). Provided furtherdownstream of the flow switch 66 are a pressure sensor 64 and a pressuretank 70. The pressure sensor 64 is a pressure measuring device formeasuring the discharge pressure of the pump 40. The pressure tank 70 isa pressure retainer for retaining the discharge pressure while the pump40 is stopped.

Note that in the example illustrated in FIG. 2, the pump apparatus 10includes the check valves 62 a and 62 b, the pressure sensors 63 and 64,the flow switch 66, and the pressure tank 70. However, the pumpapparatus 10 may not include some of these, and some of these may beinstalled externally of the pump apparatus 10. For example, suchconfiguration is also applicable that the check valve 62 a is connectedto a primary side of the suction port 26 of the pump apparatus 10, andthe check valve 62 b is connected to a secondary side of the dischargeport 27 of the pump apparatus 10, so that the pump apparatus 10 may beconfigured to be detachable from the flow channel of the carrier liquid.In addition, the pump apparatus 10 may include other components inaddition to the components illustrated in FIG. 2. For example, the pumpapparatus 10 may include a manual valve configured such that the flowchannel of the carrier liquid can be manually opened and closed insteadof, or in addition to the check valves 62 a and 62 b.

The pump apparatus 10 includes the controller 53 for controlling thepump apparatus 10 entirely. Note that in the example illustrated in FIG.1, the controller 53 is housed in the fourth casing member 24. However,the configuration is not limited to the described example, and thecontroller 53 may be housed in another casing member and may be providedoutside the casing 20. As the controller 53, a known microprocessorcentered on a CPU may be employed, and a dedicated circuit board mayalso be employed. As illustrated in FIG. 2, the controller 53 of theembodiment includes a memory 531, an arithmetic part 532, an I/O part533, and a communication part 534.

Examples of the memory 531 include a nonvolatile memory such as ROM,HDD, EEPROM, FeRAM, and a flash memory, and a volatile memory such asRAM. The memory 531 stores a control program for controlling the pumpapparatus 10, and various data relating to the pump apparatus 10 such asapparatus information, set value information, maintenance information,history information, abnormality information, and operation information.Note that when the memory 531 includes a nonvolatile memory area, thesemay be stored in the nonvolatile memory area.

As the arithmetic part 532, used here is a CPU. The arithmetic part 532performs an arithmetic operation or the like for controlling the variousdevices which constitute the pump apparatus 10 based on the controlprogram and various data stored in the memory 531 and signals input fromthe I/O part 533. The arithmetic part 532 also performs communicationcontrol in the I/O part 533, the communication part 534 and the like.The results of the arithmetic operation performed by the arithmetic part532 are stored in the memory 531 and are output to the I/O part 533 andthe communication part 534.

Examples of the I/O part 533 include ports and terminals. The I/O part533 receives detection signals from the various sensors such as thepressure sensors 63 and 64 and the flow switch 66 and transmits thesesignals to the arithmetic part 532. Note that the pressure sensors 63and 64 and the flow switch 66 are examples of the sensor 54 illustratedin FIG. 1. As other examples of the sensor 54, the detection signalsfrom the sensor for detecting the temperature of the inverter 51, thedetection signals from the sensor for detecting the number of rotationsof the motor 30 may be input to the I/O part 533. The I/O part 533 ismutually connected to the inverter 51 and to the PLC unit 52. For theconnection of the I/O part 533 to the inverter 51 or the PLC unit 52,communication means such as the RSs 422, 232C, and 485 may be employed.

The communication part 534 transmits various types of informationrelating to the pump apparatus 10 stored in the memory 531, receiveschange of setting of the set value information or a control command ofthe pump apparatus 10 from the outside, and reflects the changes or thecommand in the control. As the wireless communication in thecommunication part 534, for example, near field communication (NFC)technology may be used. In addition, wireless communication of anyscheme, such as Bluetooth (registered trademark) and the Wi-Fi(registered trademark) may be used. However, the NFC is advantageous inthat the communication may be completed only by bringing an externaldevice close to the communication part 534 in the casing 20. As thewired communication, for example, an external connection terminal suchas USB (Universal Serial Bus) may be provided on the outer surface ofthe casing 20 so that communication by the communication part 534 isachieved by connecting the external device to the external connectionterminal, or a serial communication such as RS 422, RS 232C, RS 485 orthe like may be used.

The controller 53 of the embodiment is assumed to exchange signals withan external device 80 via the communication part 534 or the PLC unit 52,and the pump apparatus 10 itself does not include a control panel thatfunctions as a user interface. Assumed examples of the external device80 that communicates with the controller 53 include, for example,general-purpose terminal devices such as smartphones, mobile phones,personal computers, and tablets, or a dedicated terminal device for thepump apparatus 10. However, the configuration is not limited to thedescribed example, and the pump apparatus 10 may be configured toinclude a control panel configured to be able to communicate via a wireor wirelessly with the controller 53, so that various data stored in thememory 531 can be displayed or changed by the control panel via thearithmetic part 532.

An example of control of the pump apparatus 10 by the controller 53 willbe described. When the discharge pressure drops to a predeterminedstarting pressure in a state in which the pump 40 is stopped, thecontroller 53 starts the pump 40. Specifically, the controller 53 issuesa command to the inverter 51 to start driving the pump 40. During theoperation of the pump 40, control such as estimated end pressureconstant control or target pressure constant control is performed withthe set pressure (set pressure PA). Specifically, in the case of theestimated end pressure constant control, the controller 53 sets a targetpressure SV with respect to the discharge pressure of the pump 40 usingthe number of rotations of the pump 40 and a target pressure controlcurve so that the pressure at the end of the water supply destinationbecomes constant at the minimum pressure “PB-actual lifting height”. Inthe case of the target pressure constant control, the controller 53 setthe set pressure PA to the target pressure SV so that the pressure onthe discharge side of the pump 40 becomes the set pressure PA. In bothcases of the estimated end pressure constant control and the targetpressure constant control, the controller 53 sets the discharge pressuredetected by the pressure sensor 64 as a current pressure PV. Then, a PIDcalculation is performed based on the deviation between the targetpressure SV and the current pressure PV, whereby a command rotationspeed of the pump 40 is set. Note that in the estimated end pressureconstant control, the set pressure PA is a pressure value at the maximumflow rate, and the minimum pressure PB is a pressure value at the zeroflow rate.

When the amount of use of water in the water supply target is reducedduring the operation of the pump 40, the flow switch 66 detects the factthat the discharge flow rate from the pump 40 reaches the amount belowthe underquantity of water and sends the detection signal to thecontroller 53 via the I/O part 533. Upon reception of the detectionsignal, the controller 53 performs pressure accumulation operation,which is an operation to control the number of rotations of the pump 40until the discharge pressure reaches a stop pressure in a predeterminedtime. When the discharge pressure reaches the predetermined stoppressure, it is determined that the pressure is accumulated in thepressure tank 70 and the pressure accumulation operation is ended andthe pump 40 is stopped (stop due to small quantity of water). When wateris used again in the water supply target and the discharge pressuredrops to or below a starting pressure after the pump 40 is stopped dueto small quantity of water, the pump 40 is restarted. Other means suchas loading by a current value of the inverter 51 or shut-off head may beused as a method of detecting the small quantity of water without usingthe flow switch 66.

FIG. 3 is a drawing illustrating a schematic configuration of thepressure tank 70 according to the embodiment. The pressure tank 70 isconnected to downstream (secondary side) of the pump 40 (the first andsecond impellers 41 and 43 in FIG. 1) and configured to retain thedischarge pressure while the pump 40 is stopped. The pressure tank 70defines part of the flow channel of the carrier liquid carried by thepump apparatus 10. The pressure tank 70 includes a pipe-shaped pressuretank casing 72, which is opened at both ends (the upper end and thelower end in FIG. 3), and an annular-shaped bladder 74. The pressuretank casing 72 includes an enlarged diameter portion 721, and theannular-shaped bladder 74 is disposed in the enlarged diameter portion721 which has enlarged diameter. The bladder 74 is provided with anair-supply valve 741 for supplying working fluid such as nitrogen gas,for example, and the working fluid is enclosed in the bladder 74 throughthe air-supply valve 741. In this manner, in the embodiment since theoutline of the pressure tank 70 has a pipe shape, the outer shape of thepump apparatus 10 entirely including the pressure tank 70 may be formedinto a pipe shape, so that the apparatus can save space.

Note that in the embodiment the pump apparatus 10 is described to havethe pressure tank 70 having the pipe-shaped outline but is not limitedthereto. The pump apparatus 10 may be provided with a conventionalpressure tank branched and connected to the flow channel of the carrierliquid instead of, or in addition to the pressure tank 70 illustrated inFIG. 3. Alternately, the pressure tank as illustrated in FIG. 3 or theconventional pressure tank may be connected to the secondary side of thedischarge port 27 of the pump apparatus 10. In addition, the pumpapparatus 10 may not be provided with the pressure tank, for example,when the discharge port 27 is connected to the water receiving tank (seea pump apparatus 10A in FIG. 7).

According to the pump apparatus 10 of the embodiment described above,the motor 30 and the inverter 51 are housed in the interior of thepipe-shaped casing 20. Accordingly, the apparatus can save space. Inaddition, since the motor 30 and the inverter 51 are disposed in thevicinity of the flow channel of the carrier liquid, the heat dissipationof the motor 30 and the inverter 51 may be accelerated. Furthermore,transmission of the noise generated by driving of the motor 30 and theinverter 51 to the outside, that is, the noise of the pump apparatus 10may be reduced. The casing 20 includes the first to fourth casingmembers 21 to 24 connected to each other, and the motor 30, the firstimpeller 41, the second impeller 43, and the inverter 51 are housed inthe interior of each of the first to fourth casing members 21 to 24. Inthis manner, since the components of the pump apparatus 10 is housed inthe respective casing members, maintenance work can be facilitated andcustomization of the pump apparatus 10 such as changing the number ofstages of the impellers to one, or three or more according to theapplication of the user can also be facilitated.

(Modification of Pump Apparatus)

In the pump apparatus 10 illustrated in FIG. 1, the casing 20 includesfour casing members (first to fourth casing members 21 to 24). However,the configuration is not limited to the example described above, and thecasing 20 may include one to three casing members or may include five ormore casing members. Also, in the example illustrated in FIG. 1, fromthe upstream (primary side) to the downstream (secondary side) in theflow channel direction Af, the fourth casing member 24, the first casingmember 21, the second casing member 22, and the third casing member 23are arranged in this order, but the configuration is not limited in theexample in FIG. 1. For example, such a configuration is also applicablethat at least one of the second casing member 22 and the third casingmember 23 is connected to a primary side of the first casing member 21,and the impeller is disposed upstream of the motor 30. The pumpapparatus 10 may also be configured to have the impellers on bothupstream and downstream of the motor 30.

FIG. 10 is a drawing illustrating a schematic configuration of a pumpapparatus 10X according to a modification. In the pump apparatus 10Xillustrated in FIG. 10, the same components as those in the pumpapparatus 10 illustrated in FIG. 1 are denoted by the same referencesigns, and substantially the same components are denoted by referencesigns added with X. In the description below, the description of partsoverlapping those of the pump apparatus 10 illustrated in FIG. 1 will beomitted. A casing 20X of the pump apparatus 10X illustrated in FIG. 10includes first to fourth casing members 21X to 24X. The first casingmember 21X houses the motor 30, and the fourth casing member 24X housesan inverter 51X. Also, the second and third casing members 22X and 23Xhouse first and second impellers 41X and 43X, respectively. In the pumpapparatus 10X illustrated in FIG. 10, as an example, the second casingmember 22X, the fourth casing member 24X. the first casing member 21X,and the third casing member 23X are arranged in this order in the flowchannel direction Af of the carrier liquid. The pump apparatus 10X isconfigured such that when a rotating shaft 30X of the motor 30 rotates,the first impeller 41X in the second casing member 22X and the secondimpeller 43X in the third casing member 23X rotate integrally with therotating shaft 30X of the motor 30, and the carrier liquid is pumpedfrom the suction port 26 to the discharge port 27. In other words, inthe pump apparatus 10X, the impellers are disposed on both upstream anddownstream of the motor 30. Note that although one each of the impellersis provided upstream and downstream of the motor 30 in the exampleillustrated in FIG. 10, the configuration is not limited to thedescribed example, and two or more stages of the impellers may beprovided on at least one of the upstream and the downstream of the motor30.

In addition, in the pump apparatus 10X illustrated in FIG. 10, as anexample, the first impeller 41X and the second impeller 43X are providedto pump the carrier liquid in the opposite directions. In other words,the pump apparatus 10X is configured such that the first impeller 41Xpumps the carrier liquid upward from the bottom, and the second impeller43X pumps the carrier liquid downward from the top. In thisconfiguration, a thrust force acting on the first impeller 41X and athrust force acting on the second impeller 43X may be cancelled out, andthus a force acting on the respective rotating shafts of the pumpapparatus 10X and the bearing can be reduced. Note that although theimpellers configured to pump the carrier liquid in the oppositedirections are provided both upstream and downstream of the motor 30 inthe pump apparatus 10X illustrated in FIG. 10, the configuration is notlimited to the described example, and in the pump apparatus 10illustrated in FIG. 1, for example, one of the first impeller 41 and thesecond impeller 43 may be configured to pump the carrier liquid to adirection opposite to the other.

Note that in the pump apparatus 10X, a rotating shaft 31Xa forconnecting the rotating shaft 31X of the motor 30 and a rotating shaft41Xa of the first impeller 41X is axially supported in the fourth casing24X. However, the configuration is not limited to the described example.For example, the rotating shaft 31X of the motor 30 may be configured toextend beyond the fourth casing 24X and be connected to the rotatingshaft 41Xa of the first impeller 41X.

(Example of Application to Water Supply System)

Next, an example of the water supply system using the pump apparatus 10of the embodiment will be described. Note that the pump apparatus 10X ofthe modification may be employed instead of the pump apparatus 10 in thefollowing description. FIG. 4 is a drawing illustrating an example of awater supply system using the pump apparatus 10 of the embodiment. Asillustrated in FIG. 4, the water supply system includes a first pumpapparatus 10A coupled to a water pipe (water main) 102 and a second pumpapparatus 10B coupled in series to a discharge side of the first pumpapparatus 10A. Here, the pump apparatus 10 described above is used asthe first pump apparatus 10A and the second pump apparatus 10B. Thecomponents of the first and second pump apparatuses 10A and 10Bcorresponding to those of the pump apparatus 10 described above will bedescribed with “A” and “B” suffixed to the respective signs. In theembodiment, the first pump apparatus 10A is installed on the ground orunderground, and the second pump apparatus 10B is installed in themiddle level of a building 106.

A suction port of the first pump apparatus 10A is connected to the waterpipe 102 via an introduction pipe 103. A discharge port of the firstpump apparatus 10A and a suction port of the second pump apparatus 10Bare coupled by a first water distribution pipe 104 a. The first waterdistribution pipe 104 a is coupled to respective water supply plugs(first water supply targets) 108 a of lower levels in the building 106via branch pipes 107a. A second water distribution pipe 104 b isconnected to a discharge port of the second pump apparatus 10B, and thesecond water distribution pipe 104 b is coupled to respective watersupply plugs (second water supply target) 108 b on the higher levels ofthe building via branch pipes 107 b. In this configuration, the firstpump apparatus 10A is configured to boost the pressure of water from thewater pipe 102 and supply the water to the respective water supply plugs108 a on the lower levels of the building 106. Then, the second pumpapparatus 10B further boosts the pressure of the water from the firstpump apparatus 10A and supplies the water to respective water supplyplugs 108 b on the higher levels of the building 106.

A controller 53A of the first pump apparatus 10A and a controller 53B ofthe second pump apparatus 10B are configured to communicate operationinformation with each other via so-called power line communication (PLC)using the power line 110 as a communication line. FIG. 5 is a drawingillustrating a power line communication in the embodiment. Asillustrated, the power line 110 is connected from a distribution board112 to each of the pump apparatuses 10A and 10B so that power from thecommercial power supply (system power supply 114), not illustrated, issupplied. The power from the system power supply 114 is supplied topumps 40A and 40B of the respective pump apparatuses 10A and 10B via thepower line 110. The power line 110 from the distribution board 112 isconnected to PLC units 52A and 52B of the respective pump apparatuses10A and 10B. The respective PLC units 52A and 52B are configured to becapable of performing communication through the power line 110 (seebroken line), so that mutual exchange of information between thecontrollers 53A and 53B is performed by the communication between thecontrollers 53A and 53B and the PLC units 52A and 52B.

The operation information including operation and stop of the pumps 40Aand 40B, the measurement values (discharge pressure) of pressure sensors64A and 64B, failure information of the pump apparatuses 10A and 10B,and operation commands to the pumps 40A and 40B is transmitted in bothdirection between the controller 53A and the controller 53B through thepower line 110. Such a communication function enables a coordinatedoperation between the first pump apparatus 10A and the second pumpapparatus 10B.

When only the pump 40B of the second pump apparatus 10B is operated in astate in which the pump 40A of the first pump apparatus 10A is stopped,negative pressure may be generated within the first water distributionpipe 104 a. If the water supply plugs 108 a on the lower levels areopened in this state, air may be sucked from the water supply plugs 108a. Therefore, in order to prevent such suction of air, the pump 40B isstarted after the pump 40A is started.

As described above, the pumps 40A and 40B are started when therespective discharge pressures drop to a predetermined startingpressure. Therefore, the controllers 53A and 53B each have a presetstarting pressure that triggers the pumps 40A and 40B, respectively, tostart. In addition, the controller 53A has a second starting pressureset for starting the pump 40A. The second starting pressure is a secondthreshold value for a start based on the discharge pressure of thesecond pump apparatus 10B (measurement value of the pressure sensor64B). The second starting pressure is set to be larger than the startingpressure of the pump 40B of the second pump apparatus 10B. This is forstarting the pump 40A before the pump 40B is started as described above.

The controller 53A starts the pump 40A based on two triggers: when themeasurement value of the pressure sensor 64A drops to the first startingpressure, and when the measurement value of the pressure sensor 64Bacquired via the power line communication drops to the second startingpressure. When the discharge pressure of the pump 40B drops, it willfall below the second starting pressure of the first pump apparatus 10Abefore the starting pressure of the second pump apparatus 10B. Thecontroller 53A of the first pump apparatus 10A starts the pump 40A whenthe measurement value of the pressure sensor 64A acquired through thepower line 110 (that is the discharge pressure of the pump 40B) reachesthe second starting pressure.

If water is used in the lower levels in a state in which the pump 40A isstopped, the discharge pressure of the pump 40A drops. Then, thedischarge pressure drops to the first starting pressure, the pump 40Astarts. In this mariner, the pump 40A is started based on themeasurement values of the two pressure sensors 64A and 64B.

The controller 53B of the second pump apparatus 10B preferably startsthe pump 40B after confirming the fact that the pump 40A is started. Thecontroller 53B may determine whether or not the pump 40A is startedbased on the fact that the number of rotations of the pump 40A exceeds apredetermined number of rotations (for example, 30% or 40% of the ratednumber of rotations).

When the water supply operation is stopped from the state in which boththe pump 40A and the pump 40B are operated, the pump 40B is firststopped, and then the pump 40A is stopped. Such a coordinated operationis performed based on the operation information transmitted between thecontrollers 53A and 53B. The controller 53A may determine whether or notthe pump 40B is stopped based on the fact that the number of rotationsof the pump 40B is below the predetermined number of rotations (forexample, 30% or 40% of the rated number of rotations). Such acoordinated operation can prevent the pump 40A from stopping before thepump 40B is stopped, so that negative pressure can be prevented frombeing generated in the first water distribution pipe 104 a.

(Modification of Water Supply System)

In the example illustrated in FIG. 4, two pump apparatuses 10A and 10Bare provided in the water supply system. However, the configuration isnot limited to the described example, and three or more pump apparatusesmay be provided. FIG. 6 is a drawing illustrating a schematicconfiguration of a water supply system according to a modification. Thewater supply system illustrated in FIG. 6 includes three pumpapparatuses 10A to 10C. The pump apparatus 10 described above may beemployed as the pump apparatuses 10A to 10C. The first pump apparatus10A is connected to the water pipe 102 via the introduction pipe 103 inthe same manner as the water supply system illustrated in FIG. 4. Thesecond pump apparatus 10B is provided on the discharge side of the firstpump apparatus 10A and is connected to the first pump apparatus 10A viathe first water distribution pipe 104 a. Likewise, the third pumpapparatus 10C is provided on the discharge side of the second pumpapparatus 10B and is connected to the second pump apparatus 10B via thesecond water distribution pipe 104 b. Then, the first pump apparatus 10Ais configured to boost the pressure of water from the water pipe 102 andsupply the water to the respective water supply plugs 108 a on the lowerlevels of the building 106 connected to the first water distributionpipe 104 a. Likewise, the second pump apparatus 10B is configured tofurther boost the pressure of water from the first pump apparatus 10Aand supply the water to the respective water supply plugs 108 b on themiddle levels of the building connected to the second water distributionpipe 104 b. Furthermore, the third pump apparatus 10C is configured tofurther boost the pressure of water from the second pump apparatus 10Band supply the water to respective water supply plugs 108 c on thehigher levels of the building connected to a third water distributionpipe 104 c. The first to third pump apparatuses 10A to 10C arerespectively configured to be able to communicate with each other by thepower line communication through the power line 110 of the building 106.

In the water supply system as described above, the same control as thewater supply system illustrated in FIG. 4 can be executed. In otherwords, regarding the first pump apparatus 10A and the second pumpapparatus 10B, by performing the same control as for the first pumpapparatus 10A and the second pump apparatus 10B in the water supplysystem illustrated in FIG. 4 described above, the pressure in the firstwater distribution pipe 104 a is prevented from unintentionally droppingto a lower pressure and the respective pump apparatuses 10A and 10B canbe properly controlled. Likewise, regarding the second pump apparatus10B and the third pump apparatus 10C, by performing the same control asfor the first pump apparatus 10A and the second pump apparatus 10B inthe water supply system illustrated in FIG. 4 described above, thepressure in the second water distribution pipe 104 b is prevented fromunintentionally dropping to a lower pressure and the respective pumpapparatuses 10B and 10C can be properly controlled. In other words, thesame control as for the first pump apparatus 10A and the second pumpapparatus 10B in the water supply system illustrated in FIG. 4 describedabove may be performed with the pump apparatus on the primary side(upstream) defined as the “first pump apparatus” and the pump apparatuson the secondary side (downstream) defined as the “second pumpapparatus”.

In the water supply system illustrated in FIG. 4, the first pumpapparatus 10A is based on a direct water supply system connected to thewater pipe 102 via the introduction pipe 103, and the second pumpapparatus 10B is directly connected to the first pump apparatus 10A viathe first water distribution pipe 104 a. However, the configuration isnot limited to the described example, and at least some of the pluralityof pump apparatuses in the water supply system may be based on a waterreceiving tank system in which the water receiving tank is connected tothe suction side.

FIG. 7 is a drawing illustrating a schematic configuration of a watersupply system according to another modification. The water supply systemillustrated in FIG. 7 is the same as the water supply system illustratedin FIG. 4 described above except that the respective pump apparatuses10A and 10B are based on a water receiving tank system. In the watersupply system illustrated in FIG. 7, water from the water pipe 102 isaccumulated in a water receiving tank 112A, and the primary side(suction side) of the first pump apparatus 10A is connected to the waterreceiving tank 112A via the introduction pipe 103. Likewise, water fromthe first pump apparatus 10,k is accumulated in a water receiving tank112B provided in the building 106, and the primary side (suction side)of the second pump apparatus 10B is connected to the water receivingtank 112B via a second introduction pipe 103 b. The introduction pipes103 and 103 b are provided with inlet valves (for example, solenoidvalves) 105 a and 105 b that can block the flow channels to the waterreceiving tanks 112A and 112B. Note that opening and closing of theinlet valves 105 a and 105 b may be controlled by the controllers 53Aand 53B of the pump apparatus 10A and 10B, or may be controlled by theexternal controller, not illustrated.

In the water supply system illustrated in FIG. 4 described above, thefirst pump apparatus 10A is installed on the ground or underground, andthe second pump apparatus 10B is installed in the middle level of thebuilding 106. However, the water supply system is not limited to theconfiguration in which the second pump apparatus 10B is disposed at ahigher position than the first pump apparatus 10A. The second pumpapparatus 10B may be disposed at the same height level as the first pumpapparatus 10A, or the second pump apparatus 10B may be disposed at alower position than the first pump apparatus 10A.

Furthermore, in the water supply system illustrated in FIG. 4 describedabove, the first pump apparatus 10A and the second pump apparatus 10Bare connected in series. However, the configuration is not limited tothe described example, and a plurality of pump apparatuses 10 may beconnected in parallel. In the example illustrated in FIG. 8, the firstpump apparatus 10A and the second pump apparatus 10B are connected inparallel. Likewise, in the water supply system illustrated in FIG. 4,FIG. 6 and FIG. 7, a plurality of the pump apparatuses 10 may beconnected in parallel to the introduction pipe 103 and the first waterdistribution pipe 104 a as illustrated in FIG. 8, or the plurality ofpump apparatuses 10 may be connected in parallel to the first waterdistribution pipe 104 a and the second water distribution pipe 104 b asillustrated in FIG. 8. Furthermore, in the water supply systemillustrated in FIG. 7, the plurality of pump apparatuses 10 may beconnected in parallel to a second drain pipe 104 b and a third drainpipe 104 c as illustrated in FIG. 8. In other words, an arbitrary pumpapparatus 10 may be connected to another pump apparatus 10 in parallel.Here, the pump apparatuses 10 connected in parallel may be provided onthe same level or on the same floor. In addition, in the pumpapparatuses 10 connected in parallel, at least part of the sensors 54 inthe plurality of pump apparatuses 10 may be grouped, for example, byproviding the pressure sensors 63 and 64 shared by the plurality of pumpapparatuses 10 in an integrated pipe connected to the suction port 27 ofthe respective pump apparatuses 10. In this configuration, the number ofthe sensors in the water supply system is reduce, so that the costs canbe lowered and management of the system can be facilitated.

(Example of Other Application)

The description given above is directed to the application of the pumpapparatus 10 to the water supply system. However, the application is notlimited thereto. The pump apparatus 10 described above may be used forvarious applications. For example, in a facility in which cold and hotwater are circulated in the heat exchanger for air-conditioning, a pumpis generally used in many cases. The pump apparatus 10 of the embodimentmay be applied for example to a facility in which a liquid is circulatedby the pump.

FIG. 9 is a drawing illustrating another application of the pumpapparatus. As illustrated in FIG. 9, an air conditioning facility 1000includes a pump apparatus 1100, a heat exchanger 1200, and a check valve1300, and a pipe 1400 that couples the pump apparatus 1100, the heatexchanger 1200, and the check valve 1300 for circulation. Note that inthe example illustrated in FIG. 9, the pump apparatus 10 illustrated inFIG. 1 is employed as the pump apparatus 1100, and the pump apparatus1100 includes the pump 40, the motor 30 and the inverter 51. However,the configuration is not limited to the described example, and aconfiguration in which a plurality of the pump apparatuses 10illustrated in FIG. 1 are connected in parallel and/or in series may beemployed as the pump apparatus 1100. In addition, although illustrationis omitted in FIG. 9, the air conditioning facility 1000 is alsoprovided with a controller configured to control the operation of thepump apparatus 1100, such as the controller 53, for driving the pumpapparatus.

The liquid discharged from the pump apparatus 1100 passes through thepipe 1400 and is heat-exchanged by the heat exchanger 1200, and then issucked by the pump 1100 via the check valve 1300. By the provision ofthe check valve 1300, the liquid circulates in one direction, andbackflow is prevented. In the circulation path of liquid in the airconditioning facility 1000, the fluid never flows to the outside in thenormal use, and always circulates in a predetermined direction. Notethat the check valve 1300 corresponds to the check valve 62 a describedabove.

As described above, in the pump apparatus 10 of the embodiment, themotor 30 and the inverter 51 are housed in the interior of thepipe-shaped casing 20 and thus the pump apparatus 10 (the pump apparatus1100) can save space. Therefore, the air conditioning facility providedwith such a pump apparatus 10 (pump apparatus 1100) can save space forthe air conditioning facility in whole. In addition, since the pumpapparatus 10 described above can reduce the noise, the noise of the airconditioning facility provided with the pump apparatus 10 in whole (pumpapparatus 1100) can be reduced.

The embodiment described thus far may be described in the followingmode. [Mode 1] According to Mode 1, a pump apparatus is provided, andthe pump apparatus includes a pipe-shaped casing including a suctionport and a discharge port arranged in the same straight line anddefining a flow channel that connects the suction port and the dischargeport; a motor disposed inside the casing, the motor including a rotatingshaft extending along a flow channel direction directing from thesuction port to the discharge port, a rotor rotating integrally with therotating shaft, a stator provided on an outer peripheral side of therotor, and a can for isolating a rotor chamber and a stator chamber, therotor chamber having the rotor disposed therein and the stator chamberhaving the stator disposed therein; and an inverter disposed in theinterior of the casing for exercising variable speed control over themotor. According to Mode 1, the pump apparatus which can save space andis easy to handle can be provided.

[Mode 2] According to Mode 2, the pump apparatus of Mode 1 furtherincludes a controller disposed in the interior of the casing. Accordingto Mode 2, since the controller is disposed in the interior of thepipe-shaped casing, the pump apparatus can save more space.

[Mode 3] According to Mode 3, the pump apparatus of Mode 1 or 2 furtherincludes a communication part configured to perform at least one oftransmission of information relating to the pump apparatus to theoutside, reception of a set change command for the pump apparatus fromthe outside, and reception of a control command for the pump apparatusfrom the outside.

[Mode 4] According to Mode 4, the pump apparatus of Modes 1 to 3 furtherincludes a power line communication unit configured to be able tocommunicate with the controller and is configured to be capable ofperforming communication using a power line for supplying power to thepump apparatus as a communication line. According to Mode 4, the powerline communication unit allows the pump apparatus to communicate with anexternal control panel, a monitoring device, or other pump apparatus. Byutilizing the power line as the communication line, the pump apparatuscan save space.

[Mode 5] According to Mode 5, the pump apparatus of Modes 1 to 4 furtherincludes a sensor disposed in the interior of the casing, the sensorbeing for detecting at least one of the discharge pressure of the pumpapparatus and the suction pressure of the pump apparatus. According toMode 5, the sensor is disposed in the interior of the casing, and thepump apparatus can save space.

[Mode 6] According to Mode 6, the pump apparatus of Modes 1 to 5 furtherincludes a pressure tank, and the pressure tank includes a pipe-shapedpressure tank casing having an enlarged diameter portion which hasenlarged diameter, and an annular bladder disposed in the enlargeddiameter portion. According to Mode 6, since the pressure tank isconfigured to have a pipe shape, the pump apparatus can be configured tohave a pipe shape as a whole, so that the pump apparatus can save space.

[Mode 7] According to Mode 7, the pump apparatus of Modes 1 to 6includes two or more impellers fixed to the rotating shaft. According toMode 7, the high-lift pump apparatus can be achieved.

[Mode 8] According to Mode 8, in the pump apparatus of Modes 1 to 7, thecasing includes a first casing member that houses at least the motor,and a second casing member connected to the first casing member, thesecond casing member including a first impeller having a first impellerrotating shaft configured to be connectable to the rotating shaft of themotor, and a bearing that axially supports the first impeller housedtherein. According to Mode 8, assembly, maintenance, and the like of thepump apparatus can be facilitated.

[Mode 9] According to Mode 9, in the pump apparatus of Mode 8, thecasing further includes a third casing member connected to the secondcasing member, the third casing member in which a second impeller havinga second impeller rotating shaft configured to be connectable to therotating shaft of the motor via the first impeller rotating shaft and abearing that axially supports the second impeller are housed. Accordingto Mode 9, the pump apparatus having two impellers can be achieved bycombining the second casing member in which the first impeller ishoused, and the third casing member in which the second impeller ishoused. Furthermore, by combining a casing member in which still anotherimpeller is housed, the pump apparatus having the impellers of a desirednumber of stages can be achieved.

[Mode 9] According to Mode 10, in the pump apparatus of Modes 1 to 9,the casing includes the first casing member in which at least the motoris housed, and a fourth casing member connected to the first casingmember and including the inverter housed therein. According to Mode 10,assembly, maintenance, and the like of the pump apparatus can befacilitated.

Although the embodiment of the present invention has been described thusfar, the embodiment of the present invention described above ispresented for facilitating the understanding of the present invention,and not for limiting the present invention. The present invention may bemodified and improved without departing from its gist, and as a matterof course, the present invention includes equivalents thereof. Inaddition, to the extent that at least some of the problems describedabove can be solved or at least some of the effects can be achieved, anycombination of the embodiments and variations is possible, and anycombination or omission of each of the components described in theclaims and the specification is possible.

This application claims its priority based on Japanese PatentApplication No. 2019-153911 filed on Aug. 26, 2019. The entiredisclosure of Japanese Patent Application No. 2019-153911 including thespecification, claims, drawings, and abstract is incorporated byreference in this application in its entirety. All disclosures inJapanese Patent Laid-Open No. 5-332282 (Patent Document 1) are herebyincorporated by reference in their entirety.

REFERENCE SIGNS LIST

Af flow channel direction

10 pump apparatus

20 casing

21 first casing member

22 second casing member

23 third casing member

24 fourth casing member

26 suction port

27 discharge port

30 motor

31 rotating shaft

32 rotor

33 stator

36 can

40 pump

41 first impeller

41 a first impeller rotating shaft

42 bearing

43 second impeller

43 a second impeller rotating shaft

44 bearing

51 inverter

52 PLC unit (power line communication unit)

53 controller

54 sensor

70 pressure tank

72 pressure tank casing

721 enlarged diameter portion

74 bladder

110 power line

1. A pump apparatus comprising: a pipe-shaped casing including a suctionport and a discharge port arranged in the same straight line anddefining a flow channel that connects the suction port and the dischargeport; a motor disposed inside the casing, the motor including: arotating shaft extending along a flow channel direction directing fromthe suction port to the discharge port; a rotor rotating integrally withthe rotating shaft; a stator provided on an outer peripheral side of therotor; and a can for isolating a rotor chamber and a stator chamber, therotor chamber having the rotor disposed therein and the stator chamberhaving the stator disposed therein; and an inverter disposed in theinterior of the casing for exercising variable speed control over themotor.
 2. The pump apparatus according to claim 1, further comprising acontroller disposed in the interior of the casing.
 3. The pump apparatusaccording to claim 1, further comprising a communication part configuredto perform at least one of transmission of information relating to thepump apparatus to the outside, reception of a set change command for thepump apparatus from the outside, and reception of a control command forthe pump apparatus from the outside.
 4. The pump apparatus according toclaim 1 further comprising a power line communication unit configured tobe capable of performing communication using a power line for supplyingpower to the pump apparatus as a communication line.
 5. The pumpapparatus according to claim 1, further comprising a sensor disposed inthe interior of the casing, the sensor being for detecting at least oneof a discharge pressure of the pump apparatus and a suction pressure ofthe pump apparatus.
 6. The pump apparatus according to claim 1, furthercomprising: a pressure tank, the pressure tank including: a pipe-shapedpressure tank casing having an enlarged diameter portion which hasenlarged diameter, and an annular bladder disposed in the enlargeddiameter portion.
 7. The pump apparatus according claim 1, comprisingtwo or more impellers fixed to the rotating shaft.
 8. The pump apparatusaccording to claim 1, wherein the casing comprises: a first casingmember that houses at least the motor; and a second casing memberconnected to the first casing member, the second casing member includinga first impeller having a first impeller rotating shaft configured to beconnectable to the rotating shaft of the motor, and a bearing thataxially supports the first impeller housed therein.
 9. The pumpapparatus according to claim 8, wherein the casing further comprises: athird casing member connected to the second casing member, the thirdcasing member including: a second impeller having a second impellerrotating shaft configured to be connectable to the rotating shaft of themotor via the first impeller rotating shaft; and a bearing that axiallysupports the second impeller housed therein.
 10. The pump apparatusaccording to claim 1, wherein the casing comprises: the first casingmember in which at least the motor is housed, and a fourth casing memberconnected to the first casing member and including the inverter housedtherein.